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Known issues for the Capture.U app

These issues are known to exist in the current version of the Capture.U app.

IssueWorkaround
When you capture and export joint angles in AR Visualization mode, the time step between frames is inconsistent.None
When you capture to video with the phone or tablet laid flat on a horizontal surface, the video that is recorded may be rotated 90 degrees.None
In Capture.U 1.2 and later, you can't export a video directly from the export window. Emails are not sent and the Slack option window is not large enough to be usable.

For email export, use the Use Mail Drop option.

To make the Share options more accessible, try dismissing the keyboard and/or changing the device orientation.

When using Real-Time Insight mode, if you have not enabled video, the controls at the top of the screen that enable you to change the opacity of the graph and to select a dark or light version of the graph are not selectable.

If you need to change the opacity of the graph and/or to select a dark or light version of the graph, ensure video is enabled. To do this, tap the Video icon at the top right of the screen.

The data rates displayed by the Capture.U app for the magnetometer do not always reflect its true values.
In To Sensor mode and To Device mode, if you select Magnetometer only, the rate is accurately represented in the displayed information (112 Hz LowG M Recorded and 112 Hz LowG M Streamed at 112 Hz respectively).
However, if other Low G inputs are also selected, the displayed value reflects the rate of the other inputs, and the magnetometer rate is not shown.
Be aware that the rate reported in the Capture.U app for Magnetometer is only accurate if Magnetometer only is selected, that is:
  • During standard capture, the magnetometer rate is 112 Hz.
  • If Global Angles are also selected, the rate is 70 Hz. 

If other Low G inputs are also selected, the displayed value reflects the rate of the other inputs.

When displaying or exporting global angle data, Nexus attempts to remove discontinuities, caused by restricting the helical angle to rotations of less than 180 degrees, by adding or removing multiples of 360 degrees of rotation to the helical angle vector. However, when the IMU approaches its original orientation after a full 360 degree rotation, the overall rotation in the underlying data is small and the axis of rotation at this time will generally not be parallel to the overall rotation vector of the gross movement. This may lead to apparent large excursions in the helical angle and a difference in the values displayed in graphs or exported from Nexus when compared with the unadjusted values exported from CaptureU.None. However, note that although the component values differ, they still describe equivalent rotations.
In Real-Time Insight and AR Visualization modes, saving a video takes longer than expected and a gray box may be displayed.Depending on the length of your video, saving may take some time. Don't tap Save again, but wait until the video is saved.
If after waiting, the app seems unresponsive and/or a gray box is displayed, the app may have terminated. Restart the device and flush the Bluetooth.
When capturing global angles in Real-Time Insight and AR Visualization modes, data may appear to drift.

Before each trial, perform the following calibration:

  1. Start streaming global angles.
  2. Wave the sensor  in a figure-of-eight motion for at least 10 seconds.
  3. Put the sensor on a flat surface.
    Observe that X angle is 0 and the Y angle is 0 (the figure-of-eight provides enough information for the sensor to self-calibrate). However, the Z angle may have a non-zero value, depending on how it is rotated to the magnetic north.
  4. Rotate the sensor on the flat surface until Z is also 0.

After the sensors are attached to a subject, allow a few seconds for onboard calibration to initiate before starting the movement that is to be captured.

Very occasionally, if you repeatedly enter and exit AR Visualization mode by tapping Home or exiting the app, the Capture.U app unexpectedly stops.

Restart the device and flush the Bluetooth.
The ARKit 3 joint data and the Vicon IMU data is not time-synced. To synchronize the data post-capture, ensure the subject performs a foot-stamp (or any other movement that shows a clear, recognizable signal in both streams) during capture.
When Capture.U is used on an iPhone, it remains in portrait orientation, even when the phone is rotated.None: this is intended behavior. When Capture.U is used on iPhones, for optimal use of the screen proportions, it is displayed in portrait mode only.
On iPhones, graphs are always exported in portrait orientation (side-by-side).None: this is intended behavior. As iPhones are locked to portrait orientation (see above), graphs are always exported in portrait orientation (side-by-side).
In portrait orientation, iPads also export side-by-side: you can only export graphs with one graph beneath the other when an iPad is in landscape orientation.
In Real-Time Insight mode, when you set benchmarks, you can't close the Benchmark keyboard.To close the Benchmark keyboard, tap the Real-Time Insight graph.
Downloaded High G accelerometer data may exhibit "latching". This is where, when the data becomes close to zero, its value is automatically rounded to zero.None

Known issues for Capture.U Desktop

IssueWorkaround
When you connect Blue Trident sensors to a computer that is running Capture.U Desktop, you may be prompted to upgrade to an earlier version of the firmware.If you're using second-generation Blue Trident sensors, do not downgrade your sensor firmware, even if prompted to do so. If you accidentally downgrade the sensor firmware on second-generation Blue Trident sensors, return them to Vicon for reprogramming.
If you have first-generation Blue Trident sensors, you can safely downgrade their firmware, if necessary.   However, as Capture.U 1.3.1 Desktop is not compatible with firmware earlier than 10.#, if you downgrade the firmware from version 10, you must uninstall Capture.U 1.3.1 and use an earlier version of Capture.U.
Downloaded High G accelerometer data may exhibit "latching". This is where, when the data becomes close to zero, its value is automatically rounded to zero.None